Update Protobuf and add protos for CS2 (#176)

* Replace protobuf 2.6.1 with 3.21.8

* Update/add protobuf libs

* Add CS2 protos

* Remove old csgo/dota protos

* Add versioned protoc bin

* Comment out Valve's `schema` define for now

* Use ENetworkDisconnectionReason

* Fix-up `offsetof` to avoid errors on some Clang versions

thirdparty/protobuf-3.21.8/python/google/protobuf/internal/python_protobuf.cc

@@ -0,0 +1,63 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Author: qrczak@google.com (Marcin Kowalczyk)
+
+#include <google/protobuf/python/python_protobuf.h>
+
+namespace google {
+namespace protobuf {
+namespace python {
+
+static const Message* GetCProtoInsidePyProtoStub(PyObject* msg) {
+  return nullptr;
+}
+static Message* MutableCProtoInsidePyProtoStub(PyObject* msg) {
+  return nullptr;
+}
+
+// This is initialized with a default, stub implementation.
+// If python-google.protobuf.cc is loaded, the function pointer is overridden
+// with a full implementation.
+const Message* (*GetCProtoInsidePyProtoPtr)(PyObject* msg) =
+    GetCProtoInsidePyProtoStub;
+Message* (*MutableCProtoInsidePyProtoPtr)(PyObject* msg) =
+    MutableCProtoInsidePyProtoStub;
+
+const Message* GetCProtoInsidePyProto(PyObject* msg) {
+  return GetCProtoInsidePyProtoPtr(msg);
+}
+Message* MutableCProtoInsidePyProto(PyObject* msg) {
+  return MutableCProtoInsidePyProtoPtr(msg);
+}
+
+}  // namespace python
+}  // namespace protobuf
+}  // namespace google